Goodman B1370187 Primary Limit Switch Auto 130-160°F 3" LG Specs

The Goodman B1370187 Primary Limit Switch serves as the critical "safety brain" of your furnace's heat exchanger assembly. Designed specifically for Goodman, Amana, and Janitrol gas furnace series, this component is responsible for monitoring the internal plenum temperature to prevent hazardous overheating. By acting as a normally closed thermal gate, it ensures that if airflow is restricted—due to a clogged filter or a failing blower motor—the system will safely interrupt the heating cycle before damage occurs. As a Genuine OEM part, it is engineered to handle the high-static environments of modern high-efficiency furnaces with total precision.

Key Features:

• Precision Safety Monitoring: Calibrated to trigger a system shutdown at 160°F and automatically reset at 130°F, ensuring the B1370187 protects your heat exchanger from stress fractures and safety hazards.
• Genuine OEM Fitment: This factory-authorized part eliminates the mounting and calibration issues common with universal "truck stock" switches, ensuring the 3-inch probe sits perfectly in the airflow stream.
• Fixes Relay and Noise Issues: Replacing a "lazy" or worn limit switch resolves common relay clicking noises and short-cycling issues that cause uneven home heating and excessive wear on the control board.
• Heavy-Duty Construction: Built with a high-grade pressed steel enclosure for superior durability against the constant thermal expansion and contraction cycles of the HVAC cabinet.
• Safety Integration: Seamlessly integrates with the furnace's integrated ignition control board to provide real-time thermal protection and highly accurate diagnostic fault code reporting.

Product Details:

• Brand: Goodman / Amana
• Manufacturer: Daikin Comfort Technologies
• Part #: B1370187
• Weight: 0.15 lbs
• Voltage: 120V / 24V Compatible (13.3 Amps @ 120VAC)
• Temperature Open: 160°F
• Temperature Close: 130°F
• Probe Length: 3.0 Inches
• Ignition Type: Compatible with HSI (Hot Surface) and Spark Ignition systems
• Contact Type: Normally Closed (Opens on Temperature Rise)

🛠️ HVAC Depot Pro Tip:

"Take a Picture First" — Before removing the old switch, photograph the wiring orientation to ensure the 1/4" quick-connect terminals are returned to the correct poles. Diagnostic Check: If your furnace is short-cycling, check your air filters and blower wheel for dust buildup. A "tripped" limit switch is often the first sign of restricted airflow. Always verify the circuit is closed at room temperature using a multimeter before finishing the install.

Cross-Reference:

• Superseded/Legacy: B13701-87, B1370187S, 1370187, 10123529
• Drawing Numbers: 60T81, 313745, 167315
• White-Rodgers/Emerson Equivalents: 3L11-160, 60T Series

Model Compatibility:

• GMT Series (Suffixes: 045-3, 070-3, 070-4, 090-3, 090-4, 090-5, 115-5, 135-5, 140-5)
• GMNT Series (Suffixes: 040-3, 060-3, 080-4, 100-4, 120-5)
• GMS8 Series (Suffixes: 0453AA, 0703AA, 0904AA, 1155CA)
• GDS8 Series (Suffixes: 0453AA, 0703AA, 0904AA, 1155CA)
• PGC Series (Suffixes: 103060, 103080, 104100, 105120)